This project will investigate worsening of symptoms in endometriosis patients undergoing artificial reproductive techniques (ART). The study compares endometriosis patients undergoing ART to two relevant reference groups; one group consisting women undergoing ART with infertility because of factors other than endometriosis, and one group consisting women with medically treated endometriosis not undergoing ART. Symptoms of endometriosis during ART will be monitored using a questionnaire that among other questions includes the validated questionnaire Endometriosis Health Profile 30® (EHP-30®). The questionnaire is administered before starting ART and later in the cycle before the patient gets to know if she is pregnant. The questionnaires as well as data collection will be administered electronically in REDCap® which is a secure web application for building and managing online surveys and databases.